1. Field of the Art
The invention relates to a method and a device for detecting faults in or on an object whose respective form is measured and compared with a master form in order to evaluate differences between the two forms caused by faults.
2. Description of the Prior Art
A fault-free condition of technical objects is necessary in many applications for safety reasons. Mechanically stressed components often must have no structural faults at all in order to sustain the stresses encountered in operation. The objects are therefore frequently checked for faults after manufacture and after a lengthy period of operation. To reduce the expense of checking, it is best to check the objects while they are still installed. One way of detecting faults in objects is to compare their form, both the external shape and the structure, with a master form corresponding to a fault-free object and obtained by measuring an object without faults. Frequently, the actual form of an object does not correspond in its external geometry to a master shape or image because the object by the very nature of its design: for example, it is unstable and deforms during checking. In order to determine whether the object has the necessary quality in comparison with the master, it is necessary to first achieve congruence in the geometry, in order to then compare measured values of identical coordinates and to check whether non-permissible differences indicative of faults are present or not.
It is an object of the invention develop a method for detecting faults in or on an object whose actual geometry possibly differs from the master during a comparsion so that faults can be detected in spite of differences in the forms not stemming from faults. Therefore, when the respective object has, for example. A geometry differing from that of the master due to, for example, mechanical stresses present during the measuring process, these can be taken into account.